Wind Erosion

Wind erosion refers to the detachment, transport, and deposition of sediment by wind. It is a dynamic, physical process where loose, dry, bare soils are transported by strong winds. Geomorphologists and other earth scientists usually consider wind erosion as a specific subdiscipline of a more broad study of aeolian (also spelled eolian) processes. The term aeolian is derived from the Greek god Aeolus, the keeper of the winds, so aeolian processes refer to effects produced by the force of the wind interacting with surface features. Although aeolian research spans a wide range of topics, which may even include research on other planets, in this chapter we will limit our focus to erosion of soils by the wind on the Earth’s surface, and more specifically on crop land and range land. The movement of sediment by wind has been occurring for many eons, as demonstrated by aeolian cross-bedding seen in wind-blown sands of ancient sandstone bedrock. Loess deposits are ubiquitous accumulations of aeolian sediments of silt, and smaller amounts of clay and sand, derived from wind-blown glacial outwash deposits or from deserts or playa lakes. Large dune fields and sand seas around the world provide further evidence of current and past aeolian environments (Fig. 14|1). Fixed or stable dunes are no longer active in the current climate but were active sand seas or dune fields in the past. Scientists have long been interested in the direct and indirect effects of wind erosion. The earliest publication relating to aeolian processes was written by a Flemish astronomer, Godefroy Wendelin, in 1646 (Stout et al., 2009). Wendelin’s paper (Wendelin, 1646) described the purple rain of Brussels that we now recognize as wet deposition of African windblown dust. Charles Darwin collected dust over the Atlantic Ocean that had fallen during his voyages on the HMS Beagle (Darwin, 1845). Recent analysis of this dust indicated it originated from the Western Sahara and molecular-microbiological methods demonstrated the presence of many viable microbes even today (Gorbushina et al., 2007)